33 research outputs found
Nonrigid Image Registration in Digital Subtraction Angiography Using Multilevel B-Spline
We address the problem of motion artifact reduction in digital subtraction angiography (DSA) using image registration techniques. Most of registration algorithms proposed for application in DSA, have been designed for peripheral and cerebral angiography images in which we mainly deal with global rigid motions. These algorithms did not yield good results when applied to coronary angiography images because of complex nonrigid motions that exist in this type of angiography images. Multiresolution and iterative algorithms are proposed to cope with this problem, but these algorithms are associated with high computational cost which makes them not acceptable for real-time clinical applications. In this paper we propose a nonrigid image registration algorithm for coronary angiography images that is significantly faster than multiresolution and iterative blocking methods and outperforms competing algorithms evaluated on the same data sets. This algorithm is based on a sparse set of matched feature point pairs and the elastic registration is performed by means of multilevel B-spline image warping. Experimental results with several clinical data sets demonstrate the effectiveness of our approach
An Investigation into the Pantheon in Bactrian Economic Documents
In the 90s, a remarkable number of manuscripts were found in Northern Afghanistan, including economic documents, legal documents, and letters, which have become an important resource for academic studies. This paper aims to investigate the Bactrian pantheon as reflected in the economic documents of this collection. At first, these economic documents and the pantheon mentioned in them are introduced. After that, the names of the gods that were commonly used in people’s names are studied, and finally the gods of the Bactrian pantheon are discussed in detail. The conclusion is that the names of the gods in the Bactrian pantheon are not Indian but Iranian, and also the gods themselves are rather pre-Zoroastrian than originally Zoroastrian
Detection of pulmonary nodules in low-dose computed tomography using localized active contours and shape features
Background: Pulmonary nodules are symptoms of lung cancer. The shape and size of these nodules are used to diagnose lung cancer in computed tomography (CT) images. In the early stages, nodules are very small, and radiologist has to refer to many CT images to diagnose the disease, causing operator mistakes. Image processing algorithms are used as an aid to detect and localize nodules. Methods: In this paper, a novel lung nodules detection scheme is proposed. First, in the preprocessing stage, our algorithm segments two lung lobes to increase processing speed and accuracy. Second, template-matching is applied to detect the suspicious nodule candidates, including both nodules and some blood vessels. Third, the suspicious nodule candidates are segmented by localized active contours. Finally, the false-positive errors produced by vessels are reduced using some two-/three-dimensional geometrical features in three steps. In these steps, the size, long and short diameters and sphericity are used to decrease the false-positive rate. Results: In the first step, some vessels that are parallel to CT cross-plane are identified. In the second step, oblique vessels are detected using shift of center of gravity in two successive slices. In step three, vessels vertical to CT cross-plane are identified. Using these steps, vessels are separated from nodules. Early Lung Cancer Action Project is used as a popular dataset in this work. Conclusions: Our algorithm achieved a sensitivity of 90.1% and a specificity of 92.8%, quite acceptable in comparison to other related works
Advances in Liver Regeneration: Revisiting Hepatic Stem/Progenitor Cells and Their Origin
The liver has evolved to become a highly plastic organ with extraordinary regenerative capabilities. What drives liver regeneration is still being debated. Adult liver stem/progenitor cells have been characterized and used to produce functional hepatocytes and biliary cells in vitro. However, in vivo, numerous studies have questioned whether hepatic progenitor cells have a significant role in liver regeneration. Mature hepatocytes have recently been shown to be more plastic than previously believed and give rise to new hepatocytes after acute and chronic injury. In this review, we discuss current knowledge in the field of liver regeneration and the importance of the serotonin pathway as a clinical target for patients with liver dysfunction.Peer Reviewe
Advances in Liver Regeneration: Revisiting Hepatic Stem/Progenitor Cells and Their Origin
The liver has evolved to become a highly plastic organ with extraordinary regenerative capabilities. What drives liver regeneration is still being debated. Adult liver stem/progenitor cells have been characterized and used to produce functional hepatocytes and biliary cells in vitro. However, in vivo, numerous studies have questioned whether hepatic progenitor cells have a significant role in liver regeneration. Mature hepatocytes have recently been shown to be more plastic than previously believed and give rise to new hepatocytes after acute and chronic injury. In this review, we discuss current knowledge in the field of liver regeneration and the importance of the serotonin pathway as a clinical target for patients with liver dysfunction
Evaluating optimal sites for combined-cycle power plants using GIS: comparison of two aggregation methods in Iran
This study aims to use an integration of GIS and multi-criteria evaluation for combined-cycle power plant site selection and compares two aggregation methods for Iran. The information layers of the criteria are prepared in the GIS environment and then the layers standardised using fuzzy functions in IDRISI. All layers are combined using two conventional methods of fuzzy logic and weighted linear combination; from this information, the suitability maps were created. Results show that only 2.0% of the region under study is scored high-suitable using the fuzzy logic, while 21% of the area is considered as highly suitable when the weighted linear combination is used. Despite this significant difference, both approaches recommend the ideal place in the north and northwest of the study area. In conclusion, integrating GIS and multi-criteria evaluation is a comprehensive approach that improves and strengthens the suitability of site selection studies
Evaluation of the Diagnostic Efficacy of Intra Oral Digital Radiography With and Without Zoom Option Software in the Detection of Occlusal Dentinal Caries: An in Vitro Study
Background and Aim : The purpose of this study was to evaluate the diagnostic precision of zoom option of Cygnus Ritter CCD intraoral digital sensor compared to original digital radiography in the detection of occlusal dentinal caries .
 Materials and Methods : Eighty-six extracted premolars with no apparent clinical caries were selected. Two methods were used for radiography namely, digital radiography using a Cygnus Ritter CCD sensor and then zoom option was applied to the original radiographs. Four maxillofacial radiologists observed the original digital and the same radiographs with zoom option to detect occlusal dentinal caries subsequently recording it in a five-grade scale.
 Microscopic sections evaluated by a pathologist were used as the gold standard for caries detection. The data were analyzed with a proportion test and processed with SPSS maxillofacial 14 soft ware .
 Results : Statistical analysis showed a sensitivity of 52.2% (71) (CI: 95 % ) for zoom option in the detection of occlusal dentinal caries (P0.05). The ppv was calculated as 52.2% (179) (P<0/.05) and npv as 68.8% (236) (P<0.05) and the accuracy was 62.2% (214) (P<0.05).
 Conclusion : The zoom option of Cygnus Ritter CCD sensor showed a significantly higher diagnostic sensitivity, ppv, npv and accuracy compared to original digital radiographs, but the zoom option of that sensor did not show a significantly higher diagnostic specificity compared to original digital radiographs .
 Key words: Dentinal caries – Digital radiography – Digital enhancement – Image processing – Zoo